Question

What method was used to discover Pluto in 1929-1930?

1) Look at irregularities (wobbles) in the motions of Uranus and Neptune.
2) Use one of the first radio telescopes to measure cold radio waves from Pluto.
3) Look for patterns in the orbits of the moons of Neptune to see in which direction Pluto would have escaped.
4) Take pairs of photographs several days apart and 'blink' them.
5) You can't fool me; Pluto was discovered by Galileo through one of his first telescopes.

Answer 1

Pluto was discovered through the method of 'blinking' pairs of photographs taken several days apart. Clyde Tombaugh used this method to identify the faint object that turned out to be Pluto.

Step-by-step explanation:

The method that was used to discover Pluto in 1929-1930 was to take pairs of photographs several days apart and 'blink' them. A young observing assistant named Clyde Tombaugh found a faint object whose motion appeared to be about right for a planet far beyond the orbit of Neptune. By comparing the positions of the object in the two photographs, Tombaugh was able to identify Pluto.